1. Field of Invention
The present invention is related to nutritional and dermatological uses of yeast glucans.
2. Description of Related Art
Glucans are polymers of glucose. Such glucans may be derived from the cell walls of yeast. Yeast glucans containing beta (1,3)-linked glucopyranose backbones have been known to have biological activity. Specifically they have been shown to activate the immune system across kingdom lines.
Glucan extracted from yeast cell walls is known to be a potent stimulator of the immune system. Studies have indicated that parenteral administration of glucan significantly modifies host resistance to a wide variety of infectious disease induced by bacterial, fungal, viral, and parasitic organisms (DeLuzio, Trends in Pharmacological Science, 4:344-347, 1983). Glucan has also been shown to have potent antitumor activity (DeLuzio et al., Advances and Experimental Medicine and Biology, 21A:269-290, 1979). The mechanism by which glucan exerts its beneficial effects is believed to be by interaction with specific glucan receptors located on the macrophage cells. (Czop, Pathology & Immunopathology Res., 5:286-296, 1986). The above studies teach, however, a toxic effect from the parenteral administration of yeast extract beta (1-3) glucan that appears to render the product unusable. This toxic effect is believed to derive from the particulate nature of the product, and has lead to a search for an effective water soluble yeast glucan extract.
The general method for the production of glucan from yeast involves extraction with alkali followed by extraction with acid (Hassid et all, Journal of the American Chemical Society, 63:295-298, 1941). Improved methods for isolating a purified water insoluble beta (1,3) glucan extract are disclosed in this inventor's earlier patent, U.S. Pat. No. 5,223,491 ("'491 patent"), which is incorporated herein by reference in its entirety.
The '491 patent further discloses the use of yeast extract beta (1,3) glucans as dermatological agents. Because of its insolubility in water, however, the glucans taught in the '491 tend to fall out of suspension in dermatological formulations, reducing the effectiveness of such formulation and rendering such formulations aesthetically undesirable. It would therefore be desirable to have an improved beta (1,3) glucan topical formulation more suitable for dermatological use, in particular one comprising a substantially purified beta (1,3) glucan that will not fall out of suspension prior to use. It would be further desirable to have a beta (1,3) glucan product that is useful as a nutritional supplement in a broad spectrum of animals, from crustaceans to humans.